Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 7/24/1995
Publication Date: N/A
Technical Abstract: Freemartin animals were compared with normal female twins and with normal female singles for growth and carcass traits. Animals were contemporaries born during a period of three years in a comprehensive experiment aimed at increasing twinning rate by selection. Treatment protocols were the same for all birth classes. Normal single and twin females were identified for comparison to freemartin and were removed from the primary experiment because of low predicted breeding value for twinning based primarily on ovulation rate determined before an average age of 584 d. From weaning at an average age of 150 d, animals were fed a diet of 2.18 Mcal of ME/kg of DM and 11.70% CP to 584 d. From 584 d to a mean slaughter age of 696 d diet contained 3.12 Mcal of ME/kg of DM and 11.50% CP. The three birth classes differed (P<.05) in birth weight. Generally, normal singles and normal twins did not differ in postnatal growth traits or in carcass traits. Other than for birth weight, normal twins and freemartins did not differ (P>.05) in growth traits. Generally, freemartins differed (P<.05) from both normal twin and single females in carcass traits with higher (P<.01) score for marbling, smaller longissimus muscle area (P<.05), and lower (P<.01) estimated retail product percentage. USDA carcass quality grade was 92.4%, 78.4% and 82.0%, choice or prime, respectively, for freemartins, normal twins, and normal singles.